The present invention relates to a device for thoroughly mixing a plurality of elements or materials which are in a combined fluid flow. More specifically, it is currently envisioned that a device formed in accordance with the present invention will be utilized to combine fluids such as water, soap, and air to generate a high quality, relatively dry cleansing foam which might be used, for example, to clean vehicles, walls, etc. In other words, it is intended that the invention be capable of producing a relatively dry foam which remains dry even when it is moved a long distance from the generator. Nevertheless, it will be realized by those skilled in the art that the invention can be employed to thoroughly mix any combined fluid, regardless of the ultimate use of the fluid. For most purposes, however, it will be preferred that the foam be as dry as possible, i.e., have maximum expansion. In other words, if, for example, a foam is to be used as a car washing agent, it is preferred that the foam be as dry (expanded) as possible when it reaches the washing brush or application tool.
For the purposes of this disclosure, a combined fluid will be considered to be any fluid having distinct elements, e.g., soap, air, and water, which are inefficiently or not well mixed.
In the past, a wide variety of devices have been developed to mix the distinct elements in a combined fluid for one purpose or another. Such devices have often employed pumps, mixing tanks, turbulence-generating structures and machinery, etc. In most instances, the devices produced marginally satisfactory mixing, were relatively expensive, or required relatively large amounts of chemicals and/or air to produce the desired foam. In some cases, even if a good, relatively dry foam was produced, the structure was such that the foam became compressed and very wet prior to reaching the point of its use. Finally, some prior art mixers require the use of structural production materials which cause the devices to require frequent maintenance in order to produce a consistent fluid mixture.
One application for such a mixing device has recently been found in car washes and, more particularly, in self-service car washes in which the owner of the car uses a brush, mounted on a wand, to spread and rub a cleaning fluid on his car. In those applications, the car wash builder and/or owner usually provides a source of water mixed to some extent (usually poorly) with a soap. This fluid can be discharged through the wand and applied to the surface of the car to be washed. In most cases, the soap is drawn through a venturi or similar device into the water as the water passes the soap reservoir. This results in an inefficient mixture containing very little, if any, cleansing foam. Consequently, customers of such car washes are relatively dissatisfied with the results they achieve and often must pay for successive uses of the machine for a single washing. When this occurs, the customer usually does not patronize that establishment again.
As a result, a need has arisen for a device which can be utilized to mix a combined fluid, such as soap and water, preferably with air, to produce an efficiently or thoroughly mixed fluid in the form of a rich, dry, cleansing foam in a simple, economical, maintenance-free manner.